Each sensor linearly scales its signal by its Tx-scaling factor \(b_k\) , and then sends \(b_k x_{k,t}\)  to the receiver simultaneously over a MAC at time slot \(t\) .
Let \(h_{k}\)  denote the channel coefficient between sensor \(k\)  and the receiver.
We focus on the scenario that the sensor signals change much faster than the channel status. Thus, \(h_k\)  is assumed to be time-invariant [1]}.
The received signal at time slot \(t\)  is [2]}
\(y_t= \sum _{k=1}^{K} h_k b_k x_{k,t} + z_t, t \in \mathbb {N}_0,\) 
